Horner’s Syndrome

What is Horner's Syndrome? ·

Horner's Syndrome is loss of sympathetic innervation to the eye, and its surrounding structures.

How can I tell if my pet has Horner's Syndrome?

The signs associated with Horner's Syndrome are usually unilateral. They include drooping of the upper eyelid, constriction of the pupil, sinking of the eye, and elevation of the third eyelid. Not all signs are very obvious in all cases.

What causes Horner's Syndrome?

In most cases, the cause of Horner's Syndrome is idiopathic, or unknown. However, anything that can create a disruption in the nervous pathway can cause Horner's Syndrome i.e. trauma/injury, infection, and tumors.

How is Horner's Syndrome diagnosed?

Horner's Syndrome is diagnosed based upon the clinical signs found during an ophthalmic and neurologic examination. A phenylephrine test can be used to confirm the diagnosis. Causes of Horner's Syndrome due to problems within the brain, spinal cord, and chest may require further testing to find the location and cause of the problem.

How is Horner's Syndrome treated?

Treatment of Horner's Syndrome is based on the results of the diagnostic tests. For most dogs, the signs associated with idopathic Horner's Syndrome will resolve within 6 months.

Is Horner's Syndrome painful?

No.

Does Horner's Syndrome interfere with vision?

In some cases Horner's Syndrome will interfere with vision because the small pupil can be covered by the third eyelid.